Safety valve for hydraulic brakes



July 7, 1936. F. M. BENTZ SAFETY VALVE FOR HYDRAULIC BRAKES Filed May 1, 1954 2 Sheets-Sheet l Wad .ZZZezzZz July 7, 1936. F. M. BENTZ ETY VALVE FOR HYDRAULIC BRAKES SAF Filed May 1 1934 2 Sheets-Sheet 2 Patented July 7, 1936 UNITED STATES PATENT OFFICE 2,046,315 '8 SAFETY VALVE FOR HYDRAULIC BRAKES v Fred M. Bentz, Temple, Tex. 7 t Application May 1, 1934, Serial No. 723,409

2 Claims.

This invention aims to provide a simple valve mechanism whereby when one of the brakes of a vehicle becomes excessively leaky, the brake may be 'cut out, the structure being'adapted to B" be used in connection with hydraulic brakes. The invention aims, further, to provide novel means'for bleeding the valve structure, at the will ofan operator. '.It is within the province of the disclosure to improve generally and to enhance the utility of devices of that type to which the invention appertains.

With the above and other objects in view, which will appearas the description proceeds, 15' the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed,

may be made within the scope, of what is claimed, without'departing' from the spirit of the invention. I In the accompanying drawings:

M Fig. 1 shows diagrammatically, and in top plan, a portion of a motor vehicle equipped with the device forming the subject-matter of this application;

Fig. 2 is a side elevation wherein a portion of the motor vehicle is shown in relation to the 30 valve mechanism;

Fig. 3 is a top plan of the valve structure;

Fig. 4 is a vertical transverse section of the valve structure; Fig. 5 is a transverse section on the line 5-5 of Fig. 4;

Fig. 6 is. a section in which the cutting plane is at right angles to the cutting plane in Fig. 4; Fig.7 is a section on the line '|'|.of Fig. .5, parts being broken away; 40 Fig. 8 is a top plan of the guide;

Fig. 9 is an elevation of the guide. In Fig. 1 and in Fig. 2 there is shown a portion I of the frame of an automobile. The brake pedal is indicated at 2 and is movably mounted at 3, in the usual way, The brake pedal 2 is operatively connected at 4 with the master cylinder 5, the fluid reservoir being shown at 6. r

A conduit 1 connects the master cylinder 5 with the casing 8 of the device forming the subject-matter of this application. Conduits 9 connect the casing 8 with the hydraulic brakes H] which are individual to the several wheels of the vehicle. h r I Describing in detail the structure which char- =nected, and is provided on its opposite side and near its top with nipples I2 to which the the 5 duits 9 are connected. It appears inFig. 5'that the casing 8 has two parallel cylinders M, which are connected at their lower ends, by converging passages IS with the bore I6 of theinlet nipple The cylinders M are closed at their 10' lower ends by screw plugs H. The upper portions of the cylinders Mare threaded, as shown at I8. Screw plugs 19 are mounted in the threaded extensions l8 of the-cylinders |4,"'and carry insulating bushings 20, wherein binding posts 2| are mounted. U-shaped cushioning springs 22 are secured to the inner ends of the binding posts 2| and are located inthe threaded portions l8 of the cylinders l4. Tothe binding posts 2| are connectedconductors 23, having a common connection at 24 to a ground 25. A battery 26, or other source ofelectrical'energy; is interposed in the connection 24. signalsffl, for instance electric lamps, are interposed in v the conductors 23 and may be carried by a 25 housing 28, placed on the instrument board (not shownlof the vehicle or elsewhere. The casing 8 is grounded at 29, through suitable; conductors 30. The bores 3| of the outlet nipples l2 open into the threaded extensions 8 of 0 the cylinders l4. V V t Tubular valve seats 32 are threaded into-the parts I8 of the cylinders l4. These seats 32 are provided at their upper ends with upstanding, inverted, U-shaped guides or bridges 33, each having, intermediate its ends, an opening 34 shown in Figs. 8 and 4. Suitably packed piston valves 35 are mounted to reciprocate in the cylinders l4 and have stems 36 which reciprocate in the openings 34 of the guides 33 of the seats 40 32. Compression springs 31 surround the stems 36 of the piston valves 35, the upper ends of the springs abutting against the tops of the guides 33 on the valve seat members 32, the lower ends .of the springs 31 engaging the piston valves'35. In the lower part of the casing 8 (Figs. 7 and 6) there are parallel longitudinal bores 38 which terminate short of the bottom of the casing 8. Under. the impulse of the compression springs 31, the piston valves 35 move down; wardly, until the stems 36 ofthe piston valves rest at their lower ends on the bottom screw plugs H, which may be considered to be parts of the casing 8. The piston valves"35 and their stems 36 are shown. in Figs. 4 and 7, in the. Posi- 5 tionreferred to. The casing 8 has first or outer transverse'ports 39, establishing communication between the cylinders 14 and the bores 38. When the piston valves 35 are in the positions shown in Figs. 4 andr7, the firstfports 39, are below or lower than the piston valves 35. The casing "8 has second or intermediate transverse ports 40, establishing communication between the 4 and 7, the intermediate ports'are above the" V 43 exist, as shown in Figs.-. G and 7. V The valve bores 38 and the cylinders l4. When' the piston valves '35 are in the lowered position of Figs.

piston valves 35, and, like the first ports 39, are

open, as Fig. 7 will show. The second ports;

40are of smaller diameter than the first ports 39, and'because the second ports ware small,

the properhydrostatic advantage is. gained. Third or inner transverse ports 4| inlthecasing 8 establish communication between the bores .2 38 and the cylinders 14, although the third valve means ports 4| normally areclosed by nowto be described.

. =The bores 38 are enlarged' as they extend upwardly, -as shown at, andit is with these i enlarged portions of the bores thatthe third or r 2 inner ports 4| communicate Atthe juncture of the parts 38 and 42 0f the bores,,valve seats seats 43 are located betweenthe third orinner ports 4l and the'second or intermediate; ports At their jupperends, the bores 38 are'sti'll furthereenlarged, as shown at 4 4, and are there threaded to receive theheads 45 of valves 46,

the lower ends of the valves being tapered at 41-, to cooperate with the. seats 43. The heads 45"of the'valves 46 have screw driver kerfs48,

- so that the valves 46 may be'moved longitudi-,

nally, toward and away from the seats 43, to close or open the inner ports 4L; In the normal operation of the device, the valves 46close theports 4|; as shown in Fig. "7 ,The heads of the-valves 46 are housed beneath closure plugs 49 (Figs- 6 and 3) threaded into the parts V '44 of the bores. r

'Under the impulse of the brake pedal 2, the

connection 4 and-the master cylinder 5 of Fig. 2,

- the fluid is urged through the conduit l,; into the bore I6 of the nipple-11in Fig. '5, through the;

passages l5, and into the cylinders I4, belowv the piston valves 35. The piston-valves 35 are raised, the ports are closed, andas the piston valves are raised, the pressure above and-below the piston valves is transmitted through the tubular seats 32 andthrough the openings 50 V (Fig-,8) thatexist on each side of thebridge or ,guides. 33 to the conduits 9 'and to the brakes I0,

the brakes being thus applied. 7 V l In the' event that one of the brakes ;I 0 becomes inoperative, the pressure in the part 18 (Fig. 4) of the cylinder is reduced, and this reduction takes placealso, through the openings 59 of Q Fig. 8, in the cylinder-proper I4 a1s'o.-- The pressure through the passage l5of Fig. 5, be-, low the piston valve 35, then :overcomes the thrust of the spring 31', and the-piston valve l 35, together with itslstem" 36, 'moves; upwardly.

The piston valve 35 seatsagainst the lower end ot the member 32 in Fig. 4, and there, is no "discharge of pressure through .the defective brake ID, that brake being. cutout.

As the valve stern 36 moves upwardly, it en- Y gages the cushioning spring '22,and through the binding post 2|, closes the circuit through .the appropriate signal 21. The driver of the car. thus is admonished that one pair of the brakes is defective. V r

In order to bleed the system quickly and thoroughly, the plug 49 may be removed, and the valve 46 may be raised, by threading it up: wardly, the port 4| of Fig.- '7 then being placed. in wide-open relation with respect to the cylinder l4 and the bore 38. 7 Referring to Fig. '1, it will be seen that the .port 39, the bore 38 and the port 40 form-a" 'by-pass leading from the inlet end of the cylinder l4 to'lthe spaceibetween the piston 35 and 15 theguide 32,.means being provided, for checking the movement of the piston toward the inlet end of :the cylinder, under the action of the spring ,31, in such position that the pistonis between the ends 39 and 40 of the by-pass,with 20 both ends of the by-pass open. Havingthus described the invention, 'what is claimed is: r 1

- 1. In a device of the classdescribed, a casing.-; having a cylinder, one end portion'of; which is 25 smooth, the opposite end, portion ofwhich is" threaded, the, casing having an inletflocated adjacent to one endof the 'cylinder and come; municatingwith the smooth portion'of the cyl-q inder, the casing having an outlet located adjacent tothe opposite endof the cylinder and communicating with the threaded portion or, the cylinder, removable closures for both-ends ofthe cylinder, onerof the closures being ,en-

gaged with the threaded portion of the cylinder-{SQ V a valve seat and guidelocated'intermediate i the ends of the cylinder and having an open ing therethrough 'Ior.,.the-passageof fluid, the. valve seat and .guide being threaded into the' threaded portionof the cylinder; the casing having a bore located approximatelyparallelto .thei axis of the cylinde'r, the casing being provided with transversely spaced. Outer, intermediate" and, inner. transverse ports communicating atone end with the bore and communicating atithe opposite end with the smooihtortion joftthe cylinder, a valve underthe control 'offan'operator and movable in the bore, the valve nor- 1 mally closing the inner port, a piston slidable in the cylinder adjacent to the inlet and having a stem slidable in the. guide, spring means interposed beteween the guide and the piston ior moving the pistonin one direction, toward the" inlet end of the cylinder, andrneans for checking the movement of the piston, in said. one direction, under the actionfof the spring means, in such position that the pistonisfbetween the outer and intermediate ports,,the piston being movable in'an opposite direction,into engages the opening'in the gulde'andivalve seat.

2. In a device of the class described, a casing having a. cylinder, the casing having an inlet located adjacent to onejend ofjthe cylinder, the

;ment with the guide and valve seat, to close up V casing having an outlet. located adjacent to the 5;,-

opposite end of the cylinder, removable closures ior both ends of the cylinder, a removable valve, seat and guide located intermediate the ends of the cylinder and having an-opening there;

through for the passage of fluid,- the opening 7 communicating-at its ends with the respectivet end portions of the cylinder, means .for holding 1 the valve seat fixedly in the cylinder, the casing r having a bore, located approximately parallel to the axis of the cylinder, the casing being provided with transversely spaced outer, intermedite and inner ports communicating at one end with the bore and communicating at the opposite end with the cylinder, between the guide and the inlet end of thejcylinder, a valve under the control of an operator, and housed movabiy in the bore, the valve normally closing the inner port, a pistonislidable in the cylinder adjacent to the inlet and having a stem slidable in the guide, spring means interposed between the guide and the piston for moving the piston in one direction, toward the inlet end of the cylinder, and means for checking the movement of the piston, in said one direction, under the action of the spring means, in such position that the piston is between the outer and intermediate ports, the piston being movable in an opposite direction, into engagement with the guide and valve seat, to close the opening in the guide and valve seat.

mm) M. BENTZ. 

